Fuel burner with adjustable nozzle



Feb. 22, 1966 a. w. WOOD ETAL 3,236,450

FUEL BURNER WITH ADJUSTABLE NOZZLE Filed March 20, 1963 3 Sheets-Sheet lsf INVENTORS GORDON W. WOOD 8| HAROLD L. LLOYD Feb. 22, 1966 s. w. WOODETAL 3,236,460

FUEL BURNER WITH ADJUSTABLE NOZZLE Filed March 20, 1963 3 Sheets-Sheet 2INVENTORS GORDON W. WOOD 8x HAROLD L. LLOYD BY mve.

TTORNEY 1966 G. w. woon ETAL FUEL BURNER WITH ADJUSTABLE NOZZLE 3Sheets-Sheet 3 Filed March 20, 1963 CONVENTIONAL HEATING TEMPERATURE'FAR Eli) OPERATION FUEL INPUT RAIE TIME FIG.5

SPEED HEAT- SYSTEM OPERATION FUEL INPUT RATE FIG.6

I HUN REDS INVENTORS GORDON W. WOOD a BY HAROLD L. LLOYD United StatesPatent Ohio Filed Mar. 20, 1963, Ser. No. 266,568 3 Claims. (Cl.239416.4)

The present invention pertains to the art of fuel burners and moreparticularly to a fuel burner for firing an industrial furnace or thelike.

The invention is particularly applicable to a burner for firing anindustrial soaking furnace and it will be discussed with particularreference thereto; however, it is to be appreciated that the inventionhas much broader applications and may be used in various otherindustrial heating installations.

In the art of heating steel ingots and large metal castings for variousmetallurgical purposes, it has become common practice to soak the ingotsor castings for a prolonged time at a relatively high temperature. Toefficient- 1y accomplish such a large scale heating operation, there isusually provided a soaking furnace which is heated by a single fuelburner adjacent one end of the furnace. A flame is projected by theburner from the burner end of the furnace to the opposite end thereof.

In larger installations, the flame may have a length exceeding twelvefeet and the heating capacity of the flame may be greater than 500,000B.t.u. per hour. To generate such a tremendously large flame, the burnerat one end of the furnace often requires a flame projecting nozzlehaving a diameter exceeding twelve inches. A burner of this size usuallycomprises an inner fuel passage for forcing fuel outwardly into thefurnace and an annular passage for directing a combustion supportingfluid, such as air, around the outwardly propelled fuel. Such burnershave been provided with control valves, usually of the butterfly type,for controlling the heat energy imparted by the flame to the interior ofthe furnace. This is the only major adjustment heretofore provided onsuch a burner.

After a furnace of the type described has been idle for a substantialtime, it must be reheated by the one burner adjacent one end of thefurnace. If the flame issuing from the nozzle of the burner weremaintained at its maximum heating rate, i.e., B.t.u. per hour, a problemresulted in that the far end of the furnace would be beated to adestructive temperature before the remainder of the furnace reached thesoaking temperature. Consequently, to prevent rapid deterioration of thefurnace lining adjacent the end opposite the burner nozzle, the flameissuing from the nozzle was maintained at its maximum heating rate onlyuntil the opposite end of the furname reached the desired soakingtemperature. At this time, the flame was shut off, or at least theheating rate was decreased, until the furnace reached an equilibriumtemperature. This required a substantial cooling of the end remote fromthe burner and a corresponding heating of the burner end of the furnace.After the furnace reached equilibrium, a flame having a maximum heatingrate was again directed toward the opposite end of the furnace. Thisprocedure of increasing and decreasing the heating rate of the flame wascontinued until the whole furnace was raised to the desired soakingtemperature.

Such a vacillatory heating cycle required a substantial amount of timeand was expensive to control.

The present invention is directed toward a fuel burner which allows theuse of a flame having the maximum heating rate during the complete warmup cycle of a soaking furnace without causing harmful over heating ofany portion of the furnace lining.

3,236,460 Patented Feb. 22, 1966 ICC In accordance with the presentinvention, there is provided an improvement in a burner for causing anoutwardly projecting flame pattern which burner includes an annularpassage for projecting pressurized combustion supporting fluid. Theimprovement in such a burner comprises means in the annular passage foradjusting the turbulence in the fluid flowing therefrom to changeselectively the flame pattern issuing from the burner.

In accordance with another aspect of the present invention, there isprovided an improvement in a furnace having a first end and a second endand a burner mounted adjacent the first end and having a nozzledirecting a flame toward the second end. The improvement in such afurnace comprises an actuator means for changing the pattern of theflame from a first pattern that concentrates the heating effect of theflame adjacent the first end of the furnace to a second pattern whichconcentrates the heating effect of the flame adjacent the second end ofthe furnace, means for determining the temperature differential betweenthe ends of the furnace and control means for energizing the actuatormeans when the temperature differential reaches a predetermined value toselect the proper pattern for offsetting this temperature differential.

In accordance with still a further aspect of the present invention,there is provided a method of heating a furnace having a first end and asecond end which method comprises concentrating the heating effect of aflame at the first end, sensing the differential in temperature betweenthe furnace ends, concentrating the heating effect of a flame at thesecond end of the furnace after the temperature differential between theends reaches a given value and, thereafter, repeating the controlledheat concentration reversals.

The primary object of the present invention is the provision of a burnerfor causing an outwardly projecting flame pattern which burner canchange the flame heating pattern without substantially changing theheating rate of the flame.

Still a further object of the present invention is the provision of aburner for causing an outwardly projecting flame pattern which burnercan produce a long, short or intermediate length flame pattern withoutsubstantially changing the heating rate of the flame.

Yet another object of the present invention is the provision of a burnerfor causing an outwardly projecting flame pattern which burner candirect the heating effect of its flame to a remote portion of a furnaceor to a portion of the furnace adjacent the burner by only a simpleinternal adjustment.

Another object of the present invention is the provision of a burner forcausing an outwardly projecting flame pattern which burner has anannular combustion supporting fluid passage and means for controllingthe amount of turbulence in this passage for controlling the flamepattern of the burner.

Still a further object of the present invention is the provision of aburner for causing an outwardly projecting flame pattern which burnerhas an annular combustion supporting fluid chamber and adjustable bafflemeans in the annular passage for controlling the amount of turbulence ordirection of the fluid flowing in the passage which in turn controls theflame pattern of the burner.

Another object of the present invention is the provision of a furnacecontrol arrangement including a burner that can have its flame patternadjusted without substantially changing the heating rate of the flame,which arrangement has a sensing system to determine the cooler portionof the furnace and means for changing the flame pattern of the burner toconcentrate the heating effect of the flame at the determined coolerportion of the furnace.

These and other objects and advantages will become apparent from thefollowing description used to illustrate the preferred embodiment of thepresent invention as read in connection with the accompanying drawingsin which:

FIGURE 1 is a side elevational view, in section, illustrating thepreferred embodiment of the present invention;

FIGURE 2 is a front elevational view, in section, taken generally alongline 2-2 of FIGURE 1;

FIGURE 2a is a partial top view illustrating the baffle blades of thepresent invention;

, FIGURE 3 is a top, somewhat schematic, plan view illustrating anotherpreferred embodiment of the present invention;

. FIGURE 4 is a temperature strip chart showing the operationalcharacteristics of the invention as disclosed in FIGURE 3;

FIGURE 5 is a rate of temperature rise chart showing the operation ofthe prior art; and

FIGURE 6 is a rate of temperature rise chart showing the operation ofthe preferred embodiment of the present invention.

Referring now to the drawings, wherein the showings are for the purposeof illustrating a preferred embodiment of the invention only and not forthe purpose of limiting same, FIGURE 1 shows a burner A for directing aflame into furnace B through flame opening C so that the interior of thefurnace is sufficiently heated for various purposes such as soakingsteel ingots prior to rolling or heat treating large castings.

Although the burner A could assume a variety of structural features, inaccordance with the preferred embodiment of the present invention, theburner comprises a main casing 10 having a nozzle 12 adapted to extendinto flame opening C. To secure the casing 10 onto the furnace B, thecasing is provided with a mounting plate 14 and circumferentially spacedsupports 16. At the upper portion of casing 10 there is a combustionsupporting fluid inlet passage 18 which receives air having a highvolume and under a pressure of approximately 6-8 ounces per square inch.The passage is provided with a mounting flange 19 to secure anappropriate air supply line onto the casing 10. In accordance with thepreferred embodiment of the present invention, air is introduced intopassage 18; however, it is appreciated that various other combustionsupporting fluids may be used without departing-from the intended spiritof th invention.

Within casing 10 there is provided-an air plenum chamber 20 having arearwardly facing back flange 22 for mounting cover plate 24 havinggasket 26 and appropriately positioned bolts or other fastening devices28. In this manner, the chamber 20 is substantially closed for receivingpressurized fluid from passage 18 which fluid is directed through nozzle12 into opening C.

Referring again to the details of burner A, there is provided a fuelcasing 30, which is a tubular structure generally concentric withrespect to the nozzle 12 and having an internal fuel passage 32 andreduced end portions 34, 36. Adjacent the rear of casing there isprovided a further casing 38 for directing fuel into passage 32. Theforwardmost end of casing 38 is adapted to be received upon reducedportion 34 of casing 30 and the casing 38 is sealed by gasket 40 and isheld against plate 24 by appropriate fastening devices such as bolts 41.In sealing engagement with the other end of casing 38 is a gasket 42adapted to seal cap 44 held onto the casing 38 by appropriate means suchas bolts 46. Threaded opening 48 provides an access passage for fuel,such as natural gas, which is directed into passage 32 for combustionwhen mixed with the air from plenum chamber 20. Centrally disposed withrespect to cap 44 is a hub 50 which will be hereinafter described inmore detail.

is provided a control rod 52 having supported on one end thereof a cap54 which cap comprises end plate Extending coaxial-1y with respect topassage 32, there 56 with axial aperture 58, support plate 60, andsupport fingers 62 which define radially facing openings 64. At theopposite end of control rod 52 there is provided a reduced portion 66having a stop 68 secured thereto and terminating in a threaded end 70.The threaded end is received within threaded bore 72 of hub 50 so thatrotation of control rod 52 by a handle 74 adjusts the outwardlyextending distance of cap 54 with respect to the end of passage 32. Withthe cap 54 in the position shown in FIGURE 1, fuel entering inlet 48 andpassing through passage 32 is directed into nozzle 12 in both an axialdirection through aperture 58 and a radial direction through openings64. This disperses the fuel in the nozzle to control the quality of theflame passing through opening C in a manner which will be describedlater. To secure the rod 52 in the desired axial position with respectto passage 32, there is provided a lock bolt 76 adapted to apply apressure to fiber slug 78 so that the end 70 is secured within bore 72in any desired position. Gasket 80 is utilized for preventing egress offuel through the bore 72.

Referring now to the forwardmost end of casing 30, there is provided asupport ring 9% attached onto reduced portion 36 by a sleeve 94 andlocked into position by a bolt 96. The support ring defines an annularcombustion supporting fluid passage 92 generally concentric with respectto passage 32 and terminating in an annular outlet 92a as shown inFIGURES 1 and 2. The combustion supporting fluid can pass through thepassage 92 and around the fuel being projected through aperture 58 andopening 64. Facing rearwardly from ring there is provided spacedgenerally parallel guide pins 93 secured onto ring 90 by lock pins 100.To center the ring 90 with respect to the nozzle 12, there is provided aplurality of circumferentially spaced centering pegs 102.

The operation of burner A as so far defined comprises propelling fuelthrough passage 32, which fuel is mixed with combustion supporting fluidflowing through passage 92. By providing an appropriate igniter in tube108, the fuel and air mixture is ignited and continues to burn to form aflame which is projected through opening C into furnace B.

To produce a clear flame, the cap 54 is adjusted in the position shownin FIGURE 1. In this manner, fuel flows through radial openings 64 whereit is quickly combusted to produce a clear blue flame. To produce aluminous or yellow flame, handle 74 is rotated to retract cap 54 intopassage 32 so that fuel from passage 32 is propelled into the furnace Bin a core surrounded by air from passage 92. In this manner, the naturalgas or other hydrocarbon fuels tend to crack, because of the heat of thefurnace and the flame, which produces a yellow luminous flame. Theparticular flame desired is dictated by the wishes of the furnaceoperator through manipulation of handle 74.

In accordance with the present invention, there is provided a means forcontrolling the amount of turbulence in the combustion supporting fluidpassing from plenum chamber 20 through annular passage 92. In accordancewith the illustrated embodiment of the present invention, such a meansis a baffle means however, it is appreciated that various means could bedevised for accomplishing the desired result. Baflie means 110 comprisesan inner sleeve 112, an outer sleeve 114 and radial support braces 116joining the sleeves to produce a unitary element or rim. There areprovided a number of circumferentially spaced blades 120 on theoutwardly facing surface of sleeve 114 as is best shown in FIGURES 2 and2a. Each of these blades comprises a mounting end 122 which is securedby appropriate means onto the sur-' face of sleeve 114 and a baffleplate portion 124 which actually causes a turbulence of the fluidflowing through passage 92. The plate 124 forms an angle a with respectto the normal direction of flow of fluid through passage 92. Inaccordance with the preferred embodiment of the present invention, anglea is approximately however, it is appreciated that various other anglesmay be provided which will produce the desired turbulence as will beexplained later. An angle of has also been used with some success. It isappreciated that the blades 120 should impart only slight aerodynamicdrag or loss to the fluid flowing through passage 92. In other words,the plates 124 should cause the fluid in passage 92 to form a vortex offluid issuing from the passage 92 without substantially decreasing thevolume of flow of the fluid.

To control the amount of fluid flowing through passage 92 which isactually affected by plates 124, there is provided a means for adjustingthe axial position of the baffle plates 124 with respect to the passage92 or nozzle 12. Since the plates 124 have a forwardly facing relief125, as best shown in FIGURE 1, as the plates are shifted rearwardlywith respect to passage 92, less of the fluid passing through thepassage 92 is affected by the plates 124. Although various structurescould be accomplished for shifting the baflie means 110 rearwardly, inaccordance with the preferred embodiment of the present invention, thereis provided a control rod 126 having a shank 128 threadably receivedwithin cap 130 with a sealing gasket 132 to prevent egress of air fromplenum chamber 20. The rearwardmost end of rod 126 terminates in handle134 that may be rotated to axially shift rod 126. To secure the rod 126in the desired axial position, there is provided a lock bolt 136 and afiber slug 138 similar to the corresponding bolt 76 and slug 78 whichhave been previously discussed.

In operation, adjustment of the axial position of battle means 110changes the amount of turbulence created by the baflle means on thefluid flowing through passage 92; however, there is very little volumeloss of combustion supporting fluid from such turbulence. Accordingly,the amount of heat caused by the combustion of the fuel flowing throughpassage 32 and the fluid flowing through passage 92 is not substantiallychanged. When the means 110 is positioned in the forwardmost location asshown in FIGURE 1, the baffle means affects substantially all of thefluid flowing through passage 92 so that the fluid is created into avortex which swirls outwardly and causes a flame generated by the burnerto be located substantially adjacent the exit end of nozzle 12. When thehandle 134 is rotated to shift the bafile means 110 rearwardly on pins98, the plates 124 are shifted from their position within annularpassage 92 so that fluid flowing through passage 92 is not swirled andis propelled outwardly across the furnace B so that the main heatingeffect of the flame caused by the burner A is substantially remote fromthe end of nozzle 12.

In this manner, by simple manipulation of rod 126 a flame having a longpattern can be provided for heating the opposite end of the furnace or aflame having a short pattern, i.e. caused by the vortex or turbulence ofthe air flowing through passage 92, for heating the furnace adjacent theburner end. This ability to change the flame pattern issuing from theend of the burner A is a substantial advantage in an industrial burnerand allows improved control of the heating effect caused by the burnerwithout decreasing the actual heating rate, i.e. the B.t.u. per hourproduced by the burner. In essence the means 110 changes the directionof the air flowing through pas-sage 92 when in its forwardmost positionto produce a short flame and does not change the direction substantiallywhen shifted to its backwardmost position which produces a long flame.

Referring now to FIGURE 3, the burner A is utilized for heating theinterior of furnace B by passing the flame through opening C. The burnerA has an outwardly extending control rod 126a which correspondssubstantially to the control rod 126 as shown in FIGURE 1 with theexception that the control rod 126a reciprocates from a first positionwith means in the forwardmost location to a second position with means110 in the backwardrnost location. In other words, the infinitelyvariable arrangement as shown in FIGURE 1 is eliminated and the means110 is shifted from one position to another to produce either a longflame or a short flame. Inlet 48 is provided with a butterfly valve 140and passage 18 is provided with a similar butterfly valve 142. Thesevalves are controlled by motors 144, 146, respectively, which motorsactuate the butterfly valve in accordance with signals received frommotor controls 148, receiving power from sources 151. A temperaturesensor such as thermocouple 152 is positioned within furnace B to sensethe average temperature within the furnace. By introducing a signal fromthermocouple 152 into controls 148, 150 the valves 140, 142 arecontrolled to regulate the heating rate, i.e. B.t.u. per hour, of theflame issuing through opening C.

To control the position within the furnace wherein the heat isconcentrated irrespective of the heating rate of the flame, there isprovided a fluid motor having an actuator arm 161 which arm shifts rod126a from its first to its second position which positions are shown insolid and dashed lines. When the arm 161 is in its forwardmost positionas shown in dashed lines, the bafiie means 110 is in its forwardmostposition within passage 92; therefore, turbulence is imparted to thefluid flowing through the passage so that the flame issuing throughopening C remains substantially adjacent the opening. This is depictedby the heating or flame pattern shown in dashed lines within thefurnace. When the motor 160 shifts the arm 161 to the solid lineposition, baffle means 110 is retracted from passage 92 so that theflame or heating pattern is substantially as shown in the solid lines inthe furnace B. In this manner, operation of arm 161 changes the heatingor flame pattern within furnace B from one pattern which tends to heatthe rear end of the furnace to a second pattern which tends to heat thefront end of the furnace. This alternation between heating or flamepatterns is advantageously utilized in heating the furnace and inmaintaining the temperature of the furnace during operation.

Adjacent the front or burner end of the furnace B there is provided atemperature sensor 162 and at the rear end of the furnace there isprovided a second temperature sensor 164. These temperature sensors atthe ends of the furnace are directed into a differential control 166which directs a signal to motor 160 in accordance with the difference intemperature sensed by sensors 162 and 164. The differential control 166is so constructed that when the temperature adjacent sensor 164 is agiven value over the temperature adjacent sensor 162, motor 160 isactuated to shift arm 161 in its forward position. In this manner, theheating pattern is changed so that the major amount of heat is directedtoward the front furnace B adjacent sensor 162. After operation in thisposition, the sensor 162 will be heated to a temperature greater thanthe sensor 164 and when the differential in temperature is suflicient,the control 166 will again signal motor 160 to shift the arm 161 intoits rearwardmost position to change the heating or flame pattern to apattern which will concentrate the heat energy adjacent sensor 164.

FIGURE 4 shows a temperature strip chart of continuous operation offurnace B, the solid line indicating the temperature at the burner endand the dashed line indicating the temperature adjacent the rear end ofthe furnace. When the temperature adjacent the burner is at a presetmaximum value t rod 126 is pulled back and the flame is made long toheat the far end of the furnace; thereafter, when the temperatureadjacent the rear end is at a preset maximum z the rod is pushed forwardto cause a short flame for heating the furnace adjacent the burner. Theamount of fuel and combustion supporting fluid is controlled by thetemperature of the furnace as sensed by thermocouple 152, It isapreciated that the differential control 166 also controls the positionof arm 161 in accordance with maximum temperatures, i.e. t and t as wellas by preset temperature differentials. The maximum temperature controlis more appropriate for continuous operation whereas the differentialcontrol is more appropriate for warm-up of the furnace as will bedescribed.

Referring now to FIGURE 5, if the only control in furnace B wasthermocouple 152 for controlling the heating rate of the flame issuingfrom burner C, the flame issuing from the burner would heat therearwardmost portion of the furnace first. To prevent overheating ofthis portion of the furnace during the initial warm-up of the furnace,

.the fuel in ut rate or heating rate of the burner B as shown in thephantom line of FIGURE would have to be decreased during the warm-upperiod. Accordingly, before the furnace is completely heated to thedesired operation temperature, the heating adjacent the far end must beslowed to allow the temperature to gradually increase adjacent theburner end of the furnace. This consumes a substantial amount of timeand is thus disadvantageous.

Referring to FIGURE 6, as the temperature of the far end of furnace Bincreases a given amount over the temperature at the near end of thefurnace, the flame or heating pattern is shifted to the near end of thefurnace as has been explained without decreasing the fuel input rate tothe furnace. By repeatedly reversing the heat concentration adjacent theopposite ends of the furnace, maximum fuel input rate may be maintainedwhile the furnace is being raised to operation temperature. Thissubstantially decreases the time for heating the furnace and thus savesthe expense of the warm-up delay as exhibited in the prior artrepresented by FIGURE 5.

If the charge within furnace B is not uniform, the sensor 152 may notprovide accurate control within the furnace and portions of the furnacemay be substantially higher in temperature than indicated by thissensor. This problem is completely eliminated by the use of the dualtemperature sensors and differential control as shown in FIGURE 6 or themaximum temperature control as shown in FIGURE 4.

The present invention has been discussed in connection with certainstructural embodiments; however, it is appreciated that variousstructural changes may be made without departing from the intendedspirit and scope of the present invention as defined by the appendedclaims.

Having thus described our invention, we claim:

1. In a burner for causing an outwardly projecting flame patternincluding a nozzle, a centrally located casing with a first outlet fordirecting fuel through said nozzle, means forming a substantiallyannular passage within said burner, around said casing and coaxial withsaid casing, said passa-ge forming means including an outer cylindricalwall in said burner and an inner cylindrical wall, said passage havingan annular second outlet adjacent the same end of said nozzle as saidfirst outlet whereby said second outlet is concentric with the firstoutlet, said second outlet having a substantially fixed cross-sectionand means directing pressurized combustion supporting fluid through saidpassage and out said second outlet, the improvement comprising:adjustable means in said annular second outlet for adjusting theturbulence of said fluid flowing therethrough to change said flamepattern between a pattern concentrated at said outlets and a patternremote from said outlet without substantially changing the amount offluid flowing through said annular second outlet, said turbulenceadjusting means comprising a plurality of blades extending radiallywithin said passage and mounted on said inner wall, each of said bladesforming an angle with the axis of said annular passage, said bladestapering downwardly from a height generally matching the width of saidsecond Outlet at the rear of said blades to a height substantially lessthan the width of said second outlet at the front of said blades, andmeans for moving said blades and inner wall as a unit, in unison,axially within said passage between a rearwardmost position where thelesser height portions of said blades are within the second outlet'ofsaid annular passage to impart a lesser amount of turbulence to saidfluid flowing therethrough and a forwardmost position where the greaterheight portions of said blades are within the second outlet of saidannular passage to impart a greater amount of turbulence to said fluidflowing therethrough.

2. The improvement as defined in claim 1 wherein said blades form anangle generally in the range of 30-45 with respect to the axis of theannular passage.

3. In a burner for causing an outwardly projecting flame patternincluding a nozzle, a centrally located casing with a first outlet fordirecting fuel through said nozzle, means forming a substantiallyannular passage within said burner, around said casing and coaxial withsaid casing, said passage forming means including an outer cylindricalwall in said burner and an inner cylindrical wall, said passage havingan annular second outlet adjacent the same end of said nozzle assaidfirst outlet whereby said second outlet is concentric with the firstoutlet, said second outlet having a substantially fixed cross-sectionand means directing pressurized combustion supporting fluid through saidpassage and out said second outlet, the improvement comprising:adjustable means in said annular second outlet for adjusting theturbulence of said fluid flowing therethrough to change said flamepattern between a pattern concentrated at said outlets and a patternremote from said outlet without substantially changing the amount offluid flowing through said annular second outlet, said turbulenceadjusting means comprising a plurality of blades each of which istapered downwardly in a direction radial of said passage and is disposedat an angle with respect to the axis of said passage, said blades beingmounted on said inner wall, and means for moving said blades and innerwall as a unit, in unison, axially within said passage between arearwardmost position where the lower parts of said tapered blades arewithin said second outlet to impart a lesser amount of turbulence tosaid fluid flowing therethrough and a forwardmost position where thehigher parts of said tapered blades are within said second outlet toimpart a greater amount of turbulence to said fluid flowingtherethrough.

References Cited by the Examiner UNITED STATES PATENTS 1,412,023 4/1922Erickson 158-1.5 1,436,823 11/1922 Purnell 158-1.5 1,893,533 1/1933Barber 158-109 2,124,175 7/1938 Zink 158-11 2,616,493 11/1952 Winters158-76 2,795,409 6/1957 Hall 263-15 2,855,033 10/1958 Furczyk 158-1092,936,829 5/1960 Braconier et al 158-109 3,081,944 3/1963 Sherman 236-153,154,134 10/1964 Bloom 158-109 FREDERICK L. MATTESON, JR., PrimaryExaminer.

MEYER PERLIN, JAMES W. WESTHAVER,

Examiners.

1. IN A BURNER FOR CAUSING AN OUTWARDLY PROJECTING FLAME PATTERNINCLUDING A NOZZLE, A CENTRALLY LOCATED CASING WITH A FIRST OUTLET FORDIRECTING FUEL THROUGH SAID NOZZLE, MEANS FORMING A SUBSTANTIALLYANNULAR PASSAGE WITHIN SAID BURNER, AROUND SAID CASING AND COAXIAL WITHSAID CASING, SAID PASSAGE FORMING MEANS INCLUDING AN OUTER CYLINDRICALWALL IN SAID BURNER AND AN INNER CYLINDRICAL WALL, SAID PASSAGE HAVINGAN ANNULAR SECOND OUTLET ADJACENT THE SAME END OF SAID NOZZLE AS SAIDFIRST OUTLET WHEREBY SAID SECOND OUTLET IS CONCENTRIC WITH THE FIRSTOUTLET, SAID SECOND OUTLET HAVING A SUBSTANTIALLY FIXED CROSS-SECTIONAND MEANS DIRECTING PRESSURIZED COMBUSTION SUPPORTING FLUID THROUGH SAIDPASSAGE AND OUT SAID SECOND OUTLET, THE IMPROVEMENT COMPRISING:ADJUSTABLE MEANS IN SAID ANNULAR SECOND OUTLET FOR ADJUSTING THETURBULENCE OF SAID FLUID FLOWING THERETHROUGH TO CHANGE SAID FLAMEPATTERN BETWEEN A PATTERN CONCENTRATED AT SAID OUTLETS AND A PATTERNREMOTE FROM SAID OUTLET WITHOUT SUBSTANTIALLY CHANGING THE AMOUNT OFFLUID FLOWING THROUGH SAID ANNULAR SECOND OUTLET, SAID TURBULENCEADJUSTING MEANS COMPRISING A PLURALITY OF BLADES EXTENDING RADIALLYWITHIN SAID PASSAGE AND MOUNTED ON SAID INNER WALL, EACH OF SAID BLADESFORMING AN ANGLE WITH THE AXIS OF SAID ANNULAR PASSAGE, SAID BLADESTAPERING DOWNWARDLY FROM A HEIGHT GENERALLY MATCHING THE WIDTH OF SAIDSECOND OUTLET AT THE REAR OF SAID BLADES TO A HEIGHT SUBSTANTIALLY LESSTHAN THE WIDTH OF SAID SECOND OUTLET AT THE FRONT OF SAID BLADES, ANDMEANS FOR MOVING SAID BLADES AND INNER WALL AS A UNIT, IN UNISON,AXIALLY WITHIN SAID PASSAGE BETWEEN A REARWARDMOST POSITION WHERE THELESSER HEIGHT PORTIONS OF SAID BLADES ARE WITHIN THE SECOND OUTLET OFSAID ANNULAR PASSAGE TO IMPART A LESSER AMOUNT OF TURBULENCE TO SAIDFLUID FLOWING THERETHROUGH AND A FORWARDMOST POSITION WHERE THE GREATERHEIGHT PORTIONS OF SAID BLADES ARE WITHIN THE SECOND OUTLET OF SAIDANNULAR PASSAGE TO IMPART A GREATER AMOUNT OF TURBULENCE TO SAID FLUIDFLOWING THERETHROUGH.